Myxobacteria from animal dung pellets collected from northwestern Himalayas: A new source of di-isobutyl phthalate.

Abstract

Myxobacteria have emerged as a rich manufacturer of a wide array of natural products captivating both the academic and drug discovery communities. Attempts to unearth novel bioactive, myxobacteria from unexploited habitats are far from exhaustion. This study reports the isolation of myxobacteria from dung pellets collected from various regions of northwestern Himalayas. The isolated myxobacteria were functionally characterized to evaluate their bioactive capability. Of all the isolates, ST/P/71 exhibited broad range activities such as anticancer against all the four human cancer cell lines with IC50 in range of 2.03-9.65 µg/ml, antimicrobial against all the tested human pathogens, also exhibiting biofilm inhibition with MBIC50 at 10.4 µg/ml against Salmonella typhimurium. Consequently, ST/P/71 was chosen for fermentation and isolation of bioactive secondary metabolite through semi-preparative HPLC. It yielded compound 1, characterized as di-isobutyl phthalate (DiBP) based on nuclear magnetic resonance (NMR) and mass data. DiBP exhibited promising cytotoxic activity against the lung cancer cell line (A549) at an IC50 values 3.09 µg/ml and biofilm inhibition activity against Bacillus subtilis and Salmonella typhimurium with MBIC50 2.703 and 9.263 µg/ml, respectively. ST/P/71 was identified as Myxococcus fulvus. Thus, M. fulvus ST/P/71 isolated from northwestern Himalayas is a new source of DiBP.